Finding all players in view frustrum

Hi all,

I want to implement for my seeker missile a client-side selection option. Therefore I want to have all visible players (or in my case vehicles) having a selection bitmap drawed "over" each player. Now, to archieve what I want, I was looking in the engine around searching for some kind of check to find out what players are in the view frustrum.

Does anyone have an idea where and what to search for? I already searched a bit around but wasn't very successfull.

Edit: Forgot to ask: Is it right if I use the dot product on my location and a players location and the dot product is positive, that then the player is in front of me?

Any hint greatly appreciated :-)

Martin